1. Field of the Invention
The present invention relates to a technology for engaging or disengaging a clutch by an actuator.
2. Description of Related Art
Conventional semi-automatic vehicles, which actuate an actuator to engage or disengage a clutch, control relative positions of drive-side and driven-side members of the clutch (the degree of engagement of the clutch) based on a difference in rotational speed between these members during engaging operation of the clutch (see, for example, JP-A-2001-146930).
The degree of engagement of the clutch is controlled based on the difference in rotational speed between the drive-side and driven-side members. However, this can prevent appropriate torque from being constantly transmitted via the clutch, and thus can impair riding comfort. For example, when the timing of discontinuing a half-clutch state is too early, the torque transmitted from the drive-side member to the driven-side member sharply increases. This can cause the rider to feel shocks. Maintenance of a half-clutch state until the difference in rotational speed is almost zero has also been proposed. However, this results in excessively low torque being continuously transmitted to the driven-side member for a long time period. Thus, the rider can perceive that the vehicle decelerates excessively.